Spot-on analysis. Public approval of Israeli action was already shifting heavily away within just the last 2 months. This of course before the latest debacle this past week. As the polls go, so too will Biden... Hopefully.
The other thing is Trump has basically been in campaign mode for years already. Biden and the broader coalition is only starting to ramp up now, and the fundraising has been good. As the money starts being spent that's going to certainly have some impact.
That said I'm still not convinced pollsters have managed go dial in millennials let alone zoomers.